The Northrop (later Northrop Grumman) B-2 Spirit, also known as the
Stealth Bomber, is an American heavy penetration strategic bomber,
featuring low observable stealth technology designed for penetrating
dense anti-aircraft defenses; it is a flying wing design with a crew
of two. The bomber can deploy both conventional and
thermonuclear weapons, such as eighty 500 lb (230 kg)-class
(Mk 82) JDAM Global Positioning System-guided bombs, or sixteen
2,400 lb (1,100 kg) B83 nuclear bombs. The B-2 is the only
acknowledged aircraft that can carry large air-to-surface standoff
weapons in a stealth configuration.
Development started under the "Advanced Technology Bomber" (ATB)
project during the Carter administration; its expected performance was
one of his reasons for the cancellation of the supersonic B-1A bomber.
The ATB project continued during the Reagan administration, but
worries about delays in its introduction led to the reinstatement of
the B-1 program. Program costs rose throughout development. Designed
and manufactured by Northrop, later Northrop Grumman, the cost of each
aircraft averaged US$737 million (in 1997 dollars). Total
procurement costs averaged $929 million per aircraft, which
includes spare parts, equipment, retrofitting, and software
support. The total program cost, which included development,
engineering and testing, averaged $2.1 billion per aircraft in
Because of its considerable capital and operating costs, the project
was controversial in the U.S. Congress and among the Joint Chiefs of
Staff. The winding-down of the
Cold War in the latter portion of the
1980s dramatically reduced the need for the aircraft, which was
designed with the intention of penetrating Soviet airspace and
attacking high-value targets. During the late 1980s and 1990s,
Congress slashed plans to purchase 132 bombers to 21. In 2008, a B-2
was destroyed in a crash shortly after takeoff, though the crew
ejected safely. There are 20 B-2s in service with the United States
Air Force, which plans to operate them until 2032.
The B-2 is capable of all-altitude attack missions up to 50,000 feet
(15,000 m), with a range of more than 6,000 nautical miles
(6,900 mi; 11,000 km) on internal fuel and over 10,000
nautical miles (12,000 mi; 19,000 km) with one midair
refueling. It entered service in 1997 as the second aircraft designed
to have advanced stealth technology after the Lockheed
attack aircraft. Though designed originally as primarily a nuclear
bomber, the B-2 was first used in combat dropping conventional,
non-nuclear ordnance in the
Kosovo War in 1999. It later served in
Iraq, Afghanistan, and Libya.
1.2 ATB program
1.3 Secrecy and espionage
1.4 Program costs and procurement
1.6 Further developments
2.2 Armaments and equipment
2.3 Avionics and systems
2.4 Flight controls
3 Operational history
6 Aircraft on display
7 Specifications (B-2A Block 30)
8 Individual aircraft
9 Notable appearances in media
10 See also
12 Further reading
13 External links
By the mid-1970s, military aircraft designers had learned of a new
method to avoid missiles and interceptors, known today as "stealth".
The concept was to build an aircraft with an airframe that deflected
or absorbed radar signals so that little was reflected back to the
radar unit. An aircraft having stealth characteristics would be able
to fly nearly undetected and could be attacked only by weapons and
systems not relying on radar. Although other detection measures
existed, such as human observation, their relatively short detection
range allowed most aircraft to fly undetected, especially at night.
DARPA requested information from U.S. aviation firms about
the largest radar cross-section of an aircraft that would remain
effectively invisible to radars. Initially, Northrop and McDonnell
Douglas were selected for further development. Lockheed had experience
in this field due to developing the
Lockheed A-12 and SR-71, which
included a number of stealthy features, notably its canted vertical
stabilizers, the use of composite materials in key locations, and the
overall surface finish in radar-absorbing paint. A key improvement was
the introduction of computer models used to predict the radar
reflections from flat surfaces where collected data drove the design
of a "faceted" aircraft. Development of the first such designs started
in 1975 with "the hopeless diamond", a model Lockheed built to test
Plans were well advanced by the summer of 1975, when
DARPA started the
Experimental Survivability Testbed (XST) project. Northrop and
Lockheed were awarded contracts in the first round of testing.
Lockheed received the sole award for the second test round in April
1976 leading to the
Have Blue program and eventually the
attack aircraft. Northrop also had a classified technology
demonstration aircraft, the
Tacit Blue in development in 1979 at Area
51. It developed stealth technology, LO (low observables),
fly-by-wire, curved surfaces, composite materials, electronic
intelligence (ELINT), and Battlefield Surveillance Aircraft
Experimental (BSAX). "The stealth technology developed from the
program was later incorporated into other operational aircraft
designs, including the B-2 stealth bomber".
By 1976, these programs progressed to where a long-range strategic
stealth bomber appeared viable. President Carter was aware of these
developments during 1977, and it appears to have been one of the major
reasons the B-1 was canceled. Further studies were ordered in
early 1978, by which point the
Have Blue platform had flown and proven
the concepts. During the 1980 presidential election campaign in 1979,
Ronald Reagan repeatedly stated that Carter was weak on defense, and
used the B-1 as a prime example. In return, on 22 August 1980, the
Carter administration publicly disclosed that the United States
Department of Defense was working to develop stealth aircraft,
including a bomber.
The B-2's first public display in 1988 at Palmdale, California: In
front of the B-2 is a star shape formed with five B-2 silhouettes.
The Advanced Technology Bomber (ATB) program began in 1979. Full
development of the black project followed, and was funded under the
code name "Aurora". After the evaluations of the companies'
proposals, the ATB competition was narrowed to the Northrop/
Lockheed/Rockwell teams with each receiving a study contract for
further work. Both teams used flying wing designs. The
Northrop proposal was code named "Senior Ice" and the Lockheed
proposal code named "Senior Peg". Northrop had prior experience
developing the YB-35 and YB-49 flying wing aircraft. The Northrop
design was larger while the Lockheed design included a small tail.
In 1979, designer
Hal Markarian produced a sketch of the aircraft,
that bore considerable similarities to the final design. The Air
Force originally planned to procure 165 of the ATB bomber.
The Northrop team's ATB design was selected over the Lockheed/Rockwell
design on 20 October 1981. The Northrop design received the
designation B-2 and the name "Spirit". The bomber's design was changed
in the mid-1980s when the mission profile was changed from
high-altitude to low-altitude, terrain-following. The redesign delayed
the B-2's first flight by two years and added about US$1 billion
to the program's cost. An estimated US$23 billion was
secretly spent for research and development on the B-2 by 1989.
MIT engineers and scientists helped assess the mission effectiveness
of the aircraft under a five-year classified contract during the
Secrecy and espionage
The B-2's first public flight in 1989
During its design and development, the Northrop B-2 program was a gray
project before its revelation to the public. Unlike the Lockheed
F-117 program, which was a black project, the type of military project
of which very few people knew even existed while it was being designed
and developed, more people within the United States federal government
knew about the B-2 and more information about the project was
available. Both during development and in service, there has been
considerable importance placed to the security of the B-2 and its
technologies. Staff working on the B-2 in most, if not all, capacities
have to achieve a level of special-access clearance, and undergo
extensive background checks carried out by a special branch of the Air
For the manufacturing, a former Ford automobile assembly plant in Pico
Rivera, California, was acquired and heavily rebuilt; the plant's
employees were sworn to complete secrecy regarding their work. To
avoid the possibility of suspicion, components were typically
purchased through front companies, military officials would visit out
of uniform, and staff members were routinely subjected to polygraph
examinations. The secrecy extended so far that access to nearly all
information on the program by both Government Accountability Office
(GAO) and virtually all members of Congress itself was severely
limited until the mid-1980s. Northrop (now Northrop Grumman) was
the B-2's prime contractor; major subcontractors included Boeing,
Hughes Aircraft (now Raytheon), GE, and Vought Aircraft.
In 1984, a Northrop employee, Thomas Cavanaugh was arrested for
attempting to sell classified information to the Soviet Union; the
information was taken from Northrop's Pico Rivera, California
factory. Cavanaugh was eventually sentenced to life in prison and
released on parole in 2001.
The B-2 was first publicly displayed on 22 November 1988 at United
States Air Force Plant 42 in Palmdale, California, where it was
assembled. This viewing was heavily restricted, and guests were not
allowed to see the rear of the B-2. However, Aviation Week editors
found that there were no airspace restrictions above the presentation
area and took photographs of the aircraft's then-secret rear section
with suppressed engine exhausts from the air, to the USAF's
disappointment. The B-2's (s/n 82-1066 / AV-1) first public flight was
on 17 July 1989 from Palmdale to Edwards AFB.
In October 2005, Noshir Gowadia, a design engineer who worked on the
B-2's propulsion system, was arrested for selling B-2 related
classified information to foreign countries. Gowadia was convicted
and sentenced to 32 years in prison for his actions.
Program costs and procurement
A procurement of 132 aircraft was planned in the mid-1980s, but was
later reduced to 75. By the early 1990s, the Soviet Union
dissolved, effectively eliminating the Spirit's primary Cold War
mission. Under budgetary pressures and Congressional opposition, in
his 1992 State of the Union Address, President George H.W. Bush
announced B-2 production would be limited to 20 aircraft. In 1996,
however, the Clinton administration, though originally committed to
ending production of the bombers at 20 aircraft, authorized the
conversion of a 21st bomber, a prototype test model, to Block 30 fully
operational status at a cost of nearly $500 million.
In 1995, Northrop made a proposal to the USAF to build 20 additional
aircraft with a flyaway cost of $566 million each.
The program was the subject of public controversy for its cost to
American taxpayers. In 1996, the General Accounting Office (GAO)
disclosed that the USAF's B-2 bombers "will be, by far, the most
costly bombers to operate on a per aircraft basis", costing over three
times as much as the B-1B (US$9.6 million annually) and over four
times as much as the B-52H (US$6.8 million annually). In
September 1997, each hour of B-2 flight necessitated 119 hours of
maintenance in turn. Comparable maintenance needs for the B-52 and the
B-1B are 53 and 60 hours respectively for each hour of flight. A key
reason for this cost is the provision of air-conditioned hangars large
enough for the bomber's 172 ft (52 m) wingspan, which are
needed to maintain the aircraft's stealthy properties, particularly
its "low-observable" stealthy skins. Maintenance costs are
about $3.4 million a month for each aircraft.
The total "military construction" cost related to the program was
projected to be US$553.6 million in 1997 dollars. The cost to
procure each B-2 was US$737 million in 1997 dollars, based only
on a fleet cost of US$15.48 billion. The procurement cost per
aircraft as detailed in GAO reports, which include spare parts and
software support, was $929 million per aircraft in 1997
The total program cost projected through 2004 was
US$44.75 billion in 1997 dollars. This includes development,
procurement, facilities, construction, and spare parts. The total
program cost averaged US$2.13 billion per aircraft. The B-2
may cost up to $135,000 per flight hour to operate in 2010, which is
about twice that of the B-52 and B-1.
In its consideration of the fiscal year 1990 defense budget, the House
Armed Services Committee trimmed $800 million from the B-2
research and development budget, while at the same time staving off a
motion to end the project. Opposition in committee and in Congress was
mostly broad and bipartisan, with Congressmen
Ron Dellums (D-CA), John
Kasich (R-OH), and
John G. Rowland
John G. Rowland (R-CT) authorizing the motion to
end the project—as well as others in the Senate, including Jim Exon
John McCain (R-AZ) also opposing the project.
The escalating cost of the B-2 program and evidence of flaws in the
aircraft's ability to elude detection by radar were among factors
that drove opposition to continue the program. At the peak production
period specified in 1989, the schedule called for spending
US$7 billion to $8 billion per year in 1989 dollars,
something Committee Chair
Les Aspin (D-WI) said "won't fly
financially." In 1990, the Department of Defense accused Northrop
of using faulty components in the flight control system; the threat
posed by bird ingestion potentially damaging engine fan blades also
In time, a number of prominent members of Congress began to oppose the
program's expansion, including later Democratic presidential nominee
John Kerry, who cast votes against the B-2 in 1989, 1991 and 1992
while a U.S. Senator, representing Massachusetts. By 1992, Republican
George H.W. Bush
George H.W. Bush called for the cancellation of the B-2 and
promised to cut military spending by 30% in the wake of the collapse
of the Soviet Union. In October 1995, former Chief of Staff of the
United States Air Force, General Mike Ryan, and former Chairman of the
Joint Chiefs of Staff, General John Shalikashvili, strongly
recommended against Congressional action to fund the purchase of any
additional B-2s, arguing that to do so would require unacceptable cuts
in existing conventional and nuclear-capable aircraft, and that
the military had greater priorities in spending a limited budget.
Some B-2 advocates argued that procuring twenty additional aircraft
would save money because B-2s would be able to deeply penetrate
anti-aircraft defenses and use low-cost, short-range attack weapons
rather than expensive standoff weapons. However, in 1995, the
Congressional Budget Office
Congressional Budget Office (CBO), and its Director of National
Security Analysis, found that additional B-2s would reduce the cost of
expended munitions by less than US$2 billion in 1995 dollars
during the first two weeks of a conflict, in which the Air Force
predicted bombers would make their greatest contribution; a small
fraction of the US$26.8 billion (in 1995 dollars) life cycle cost
that the CBO projected for an additional 20 B-2s.
In 1997, as
Ranking Member of the House Armed Services Committee and
National Security Committee, Congressman
Ron Dellums (D-CA), a
long-time opponent of the bomber, cited five independent studies and
offered an amendment to that year's defense authorization bill to cap
production of the bombers to the existing 21 aircraft; the amendment
was narrowly defeated. Nonetheless, Congress did not approve
funding for the purchase of any additional B-2 bombers.
A number of upgrade packages have been applied to the B-2. In July
2008, the B-2's onboard computing architecture was extensively
redesigned; it now incorporates a new integrated processing unit (IPU)
that communicates with systems throughout the aircraft via a newly
installed fiber optic network; a new version of the operational flight
program software was also developed, with legacy code converted from
JOVIAL programming language to standard C. Updates were
also made to the weapon control systems to enable strikes upon moving
targets, such as ground vehicles.
B-2 from below
On 29 December 2008, Air Force officials awarded a US$468 million
Northrop Grumman to modernize the B-2 fleet's radars.
Changing the radar's frequency was required as the U.S. Department of
Commerce had sold that radio spectrum to another operator. In July
2009, it was reported that the B-2 had successfully passed a major
USAF audit. In 2010, it was made public that the Air Force
Research Laboratory had developed a new material to be used on the
part of the wing trailing edge subject to engine exhaust, replacing
existing material that quickly degraded.
In July 2010, political analyst Rebecca Grant speculated that when the
B-2 becomes unable to reliably penetrate enemy defenses, the Lockheed
Martin F-35 Lightning II may take on its strike/interdiction mission,
carrying B61 nuclear bombs as a tactical bomber. However, in March
2012, the Pentagon announced that a $2 billion, 10-year-long
modernization of the B-2 fleet was to begin. The main area of
improvement would be replacement of outdated avionics and
It was reported in 2011 that the Pentagon was evaluating an unmanned
stealth bomber, characterized as a "mini-B-2", as a potential
replacement in the near future. In 2012, Air Force Chief of Staff
General Norton Schwartz stated the B-2's 1980s-era stealth would make
it less survivable in future contested airspaces, so the USAF is to
proceed with the
Next-Generation Bomber despite overall budget
Next-Generation Bomber was estimated, in 2012, to have a
projected overall cost of $55 billion.
In 2013, the USAF contracted for the Defensive Management System
Modernization program to replace the antenna system and other
electronics to increase the B-2's frequency awareness. The Common
Very Low Frequency Receiver upgrade will allow the B-2s to use the
same very low frequency transmissions as the Ohio-class submarines so
as to continue in the nuclear mission until the Mobile User Objective
System is fielded. In 2014, the USAF outlined a series of upgrades
including nuclear war fighting, a new integrated processing unit, the
ability to carry cruise missiles, and threat warning improvements.
Although the Air Force previously planned to operate the B-2 to 2058,
their FY 2019 budget moved up its retirement to "no later than 2032."
It also moved retirement of the B-1 to 2036 while extending the B-52's
service life into the 2050s, due to the latter's lower maintenance
costs, versatile conventional payload, and ability to carry nuclear
cruise missiles (which the B-1 is treaty-prohibited from doing). The
decision to retire the B-2 early was made because the small fleet of
20 is considered too expensive per plane to retain, with its position
as a stealth bomber being taken over with the introduction of the B-21
Raider starting in the mid-2020s.
Side view of a B-2 Spirit
The B-2 Spirit was developed to take over the USAF's vital penetration
missions, able to travel deep into enemy territory to deploy their
ordnance which could include nuclear weapons. The B-2 is a flying
wing aircraft, meaning that it has no fuselage or tail. It has
significant advantages over previous bombers due to its blend of
low-observable technologies with high aerodynamic efficiency and large
payload. Low observability provides a greater freedom of action at
high altitudes, thus increasing both range and field of view for
onboard sensors. The U.S. Air Force reports its range as approximately
6,000 nautical miles (6,900 mi; 11,000 km). At
cruising altitude, the B-2 refuels every six hours, taking on up to 50
short tons (45,000 kg) of fuel at a time.
The development and construction of the B-2 required pioneering use of
computer-aided design and manufacturing technologies, due to its
complex flight characteristics and design requirements to maintain
very low visibility to multiple means of detection. The B-2
bears a resemblance to earlier Northrop aircraft; the YB-35 and YB-49
were both flying wing bombers that had been canceled in development in
the early 1950s, allegedly for political reasons. The
resemblance goes as far as B-2 and YB-49 having the same
Approximately 80 pilots fly the B-2. Each aircraft has a crew of
two, a pilot in the left seat and mission commander in the right,
and has provisions for a third crew member if needed. For
comparison, the B-1B has a crew of four and the B-52 has a crew of
five. The B-2 is highly automated, and one crew member can sleep in
a camp bed, use a toilet, or prepare a hot meal while the other
monitors the aircraft, unlike most two-seat aircraft. Extensive sleep
cycle and fatigue research was conducted to improve crew performance
on long sorties.
Armaments and equipment
A 2,000 lb (910 kg) BDU-56 bomb being loaded onto a bomb
bay's rotary launcher, 2004
The B-2, in the envisaged
Cold War scenario, was to perform
deep-penetrating nuclear strike missions, making use of its stealthy
capabilities to avoid detection and interception throughout
missions. There are two internal bomb bays in which munitions are
stored either on a rotary launcher or two bomb-racks; the carriage of
the weapons loadouts internally results in less radar visibility than
external mounting of munitions. The B-2 is capable of carrying
40,000 lb (18,000 kg) of ordnance. Nuclear ordnance
includes the B61 and B83 nuclear bombs; the
AGM-129 ACM cruise missile
was also intended for use on the B-2 platform.
It was decided, in light of the dissolution of the Soviet Union, to
equip the B-2 for conventional precision attacks as well as for the
strategic role of nuclear-strike. The B-2 features a
sophisticated GPS-Aided Targeting System (GATS) that uses the
aircraft's APQ-181 synthetic aperture radar to map out targets prior
to deployment of GPS-aided bombs (GAMs), later superseded by the Joint
Direct Attack Munition (JDAM). In the B-2's original configuration, up
to 16 GAMs or JDAMs could be deployed; an upgrade program in 2004
raised the maximum carriable capacity to 80 JDAMs.
The B-2 has various conventional weapons in its arsenal, able to equip
Mark 82 and Mark 84 bombs, CBU-87 Combined Effects Munitions, GATOR
mines, and the CBU-97 Sensor Fuzed Weapon. In July 2009, Northrop
Grumman reported the B-2 was compatible with the equipment necessary
to deploy the 30,000 lb (14,000 kg) Massive Ordnance
Penetrator (MOP), which is intended to attack reinforced bunkers; up
to two MOPs could be equipped in the B-2's bomb bays, the B-2 is
the only platform compatible with the MOP as of 2012. As of 2011,
AGM-158 JASSM cruise missile is an upcoming standoff munition to
be deployed on the B-2 and other platforms. This is to be followed
Long Range Standoff Weapon which may give the B-2 a standoff
nuclear capability for the first time.
Avionics and systems
In order to make the B-2 more effective than previous bombers, many
advanced and modern avionics systems were integrated into its design;
these have been modified and improved following a switch to
conventional warfare missions. One system is the low probability of
AN/APQ-181 multi-mode radar, a fully digital navigation
system that is integrated with terrain-following radar and Global
Positioning System (GPS) guidance, NAS-26 astro-inertial navigation
system (first such system tested on the Northrop
SM-62 Snark cruise
missile) and a Defensive Management System (DMS) to inform the
flight crew of possible threats. The onboard DMS is capable of
automatically assessing the detection capabilities of identified
threats and indicated targets. The DMS will be upgraded by 2021 to
detect radar emissions from air defenses to allow changes to the
auto-router's mission planning information while in-flight so it can
receive new data quickly to plan a route that minimizes exposure to
A maintenance crew servicing a B-2 at Andersen AFB, Guam, 2004
For safety and fault-detection purposes, an on-board test system is
linked with the majority of avionics on the B-2 to continuously
monitor the performance and status of thousands of components and
consumables; it also provides post-mission servicing instructions for
ground crews. In 2008, many of the 136 standalone distributed
computers on board the B-2, including the primary flight management
computer, were being replaced by a single integrated system. The
avionics are controlled by 13 EMP-resistant
which are interconnected through 26 MIL-STD-1553B-busses; other system
elements are connected via optical fiber.
In addition to periodic software upgrades and the introduction of new
radar-absorbent materials across the fleet, the B-2 has had several
major upgrades to its avionics and combat systems. For battlefield
Link-16 and a high frequency satellite link have
been installed, compatibility with various new munitions has been
undertaken, and the
AN/APQ-181 radar's operational frequency was
shifted in order to avoid interference with other operator's
equipment. The arrays of the upgraded radar features were entirely
replaced to make the
AN/APQ-181 into an active electronically scanned
array (AESA) radar.
Dick Cheney inside a B-2 cockpit with pilot Capt. Luke
Jayne during a visit to Whiteman AFB, 2006
In order to address the inherent flight instability of a flying wing
aircraft, the B-2 uses a complex quadruplex computer-controlled
fly-by-wire flight control system, that can automatically manipulate
flight surfaces and settings without direct pilot inputs in order to
maintain aircraft stability. The flight computer receives
information on external conditions such as the aircraft's current air
speed and angle of attack via pitot-static sensing plates, as opposed
to traditional pitot tubes which would negatively affect the
aircraft's stealth capabilities. The flight actuation system
incorporates both hydraulic and electrical servoactuated components,
and it was designed with a high level of redundancy and
Northrop had investigated several means of applying directional
control that would least infringe on the aircraft's radar profile,
eventually settling on a combination of split brake-rudders and
differential thrust. Engine thrust became a key element of the
B-2's aerodynamic design process early on; thrust not only affects
drag and lift but pitching and rolling motions as well. Four pairs
of control surfaces are located along the wing's trailing edge; while
most surfaces are used throughout the aircraft's flight envelope, the
inner elevons are normally only in use at slow speeds, such as
landing. To avoid potential contact damage during takeoff and to
provide a nose-down pitching attitude, all of the elevons remain
drooped during takeoff until a high enough airspeed has been
The B-2's engines are buried within its wing to conceal the engines'
fans and minimize their exhaust signature
The B-2's low-observable, or "stealth", characteristics enable the
undetected penetration of sophisticated anti-aircraft defenses and to
attack even heavily defended targets. This stealth comes from a
combination of reduced acoustic, infrared, visual and radar signatures
(multi-spectral camouflage) to evade the various detection systems
that could be used to detect and be used to direct attacks against an
aircraft. The B-2's stealth enables the reduction of supporting
aircraft that are required to provide air cover, Suppression of Enemy
Air Defenses and electronic countermeasures, making the bomber a
"force multiplier". As of September 2013[update], there have been
no instances of a missile being launched at a B-2.
To reduce optical visibility during daylight flights, the B-2 is
painted in an anti-reflective paint. The undersides are dark
because it flies at high altitudes (50,000 ft or 15,000 m),
and at that altitude a dark grey painting blends well into the sky. It
is speculated to have an upward-facing light sensor which alerts the
pilot to increase or reduce altitude to match the changing illuminance
of the sky. The original design had tanks for a
contrail-inhibiting chemical, but this was replaced in production
aircraft by a contrail sensor that alerts the crew when they should
change altitude. The B-2 is vulnerable to visual interception at
ranges of 20 nmi (23 mi; 37 km) or less.
Reportedly, the B-2 has a radar cross-section (RCS) of about
0.1 m2 (1.1 sq ft). The bomber does not always fly
stealthily; when nearing air defenses pilots "stealth up" the B-2, a
maneuver whose details are secret. The aircraft is stealthy, except
briefly when the bomb bay opens. The B-2's clean, low-drag flying wing
configuration not only provides exceptional range but is also
beneficial to reducing its radar profile. The flying wing
design most closely resembles a so-called infinite flat plate (as
vertical control surfaces dramatically increase RCS), the perfect
stealth shape, as it would lack angles to reflect back radar waves
(initially, the shape of the Northrop ATB concept was flatter; it
gradually increased in volume according to specific military
Illustration of the B-2's basic radar reflection angles
RCS reduction as a result of shape had already been observed on the
Royal Air Force's
Avro Vulcan strategic bomber, and the USAF's
F-117 Nighthawk. The
F-117 used flat surfaces (faceting technique) for
controlling radar returns as during its development (see Lockheed Have
Blue) in the early 1970s, technology only allowed for the simulation
of radar reflections on simple, flat surfaces; computing advances in
the 1980s made it possible to simulate radar returns on more complex
curved surfaces. The B-2 is composed of many curved and rounded
surfaces across its exposed airframe to deflect radar beams. This
technique, known as continuous curvature, was made possible by
advances in computational fluid dynamics, and first tested on the
Northrop Tacit Blue.
The gap below the air intake has the purpose of sucking in cool air
Some analysts claim infra-red search and track systems (IRSTs) can be
deployed against stealth aircraft, because any aircraft surface heats
up due to air friction and with a two channel IRST is a CO2
(4.3 µm absorption maxima) detection possible, through
difference comparing between the low and high channel.
Burying engines deep inside the fuselage also minimizes the thermal
visibility or infrared signature of the exhaust. At the
engine intake, cold air from the boundary layer below the main inlet
enters the fuselage (boundary layer suction, first tested on the
Northrop X-21) and is mixed with hot exhaust air just before the
nozzles (similar to the Ryan AQM-91 Firefly). According to the
Stefan–Boltzmann law, this results in less energy (thermal radiation
in the infrared spectrum) being released and thus a reduced heat
signature. The resulting cooler air is conducted over a surface
composed of heat resistant carbon-fiber-reinforced polymer and
titanium alloy elements, which disperse the air laterally, in order to
accelerate its cooling. The B-2 lacks afterburners as the hot
exhaust would increase the infrared footprint; breaking the sound
barrier would produce an obvious sonic boom as well as aerodynamic
heating of the aircraft skin which would also increase the infrared
According to the Huygens–Fresnel principle, even a very flat plate
would still reflect radar waves, though much less than when a signal
is bouncing at a right angle. Additional reduction in its radar
signature was achieved by the use of various radar-absorbent materials
(RAM) to absorb and neutralize radar beams. The majority of the B-2 is
made out of a carbon-graphite composite material that is stronger than
steel, lighter than aluminum, and absorbs a significant amount of
The B-2 is assembled with unusually tight engineering tolerances to
avoid leaks as they could increase its radar signature.
Innovations such as alternate high frequency material (AHFM) and
automated material application methods were also incorporated to
improve the aircraft's radar-absorbent properties and reduce
maintenance requirements. In early 2004, Northrop Grumman
began applying a newly developed AHFM to operational B-2s. In
order to protect the operational integrity of its sophisticated radar
absorbent material and coatings, each B-2 is kept inside a
climate-controlled hangar (Extra Large Deployable Aircraft Hangar
System) large enough to accommodate its 172-foot (52 m)
A B-2 during aerial refueling which extends its range past 6,000
nautical miles (6,900 mi; 11,000 km) for intercontinental
The first operational aircraft, christened Spirit of Missouri, was
delivered to Whiteman Air Force Base, Missouri, where the fleet is
based, on 17 December 1993. The B-2 reached initial operational
capability (IOC) on 1 January 1997. Depot maintenance for the B-2
is accomplished by U.S. Air Force contractor support and managed at
Oklahoma City Air Logistics Center
Oklahoma City Air Logistics Center at Tinker Air Force Base.
Originally designed to deliver nuclear weapons, modern usage has
shifted towards a flexible role with conventional and nuclear
The B-2's combat debut was in 1999, during the Kosovo War. It was
responsible for destroying 33% of selected Serbian bombing targets in
the first eight weeks of U.S. involvement in the War. During this
war, six B-2s flew non-stop to Kosovo from their home base in Missouri
and back, totaling 30 hours. Although the bombers accounted 50 sorties
out of a total of 34,000 NATO sorties, they dropped 11 percent of all
bombs. The B-2 was the first aircraft to deploy GPS
satellite-guided JDAM "smart bombs" in combat use in Kosovo. The
use of JDAMs and precision-guided munitions effectively replaced the
controversial tactic of carpet-bombing, which had been harshly
criticized due to it causing indiscriminate civilian casualties in
prior conflicts, such as the 1991 Gulf War. On 7 May 1999, a B-2
dropped five JDAMs on the Chinese Embassy, killing several staff.
By then, the B-2 had dropped 500 bombs in Kosovo.
The B-2 saw service in Afghanistan, striking ground targets in support
of Operation Enduring Freedom. With aerial refueling support, the B-2
flew one of its longest missions to date from Whiteman Air Force Base,
Afghanistan and back. B-2s would be stationed in the
Middle East as a part of a US military buildup in the region from
The B-2's combat use preceded a U.S. Air Force declaration of "full
operational capability" in December 2003. The Pentagon's
Operational Test and Evaluation 2003 Annual Report noted that the
B-2's serviceability for Fiscal Year 2003 was still inadequate, mainly
due to the maintainability of the B-2's low observable coatings. The
evaluation also noted that the Defensive Avionics suite had
shortcomings with "pop-up threats".
Iraq War (Operation Iraqi Freedom), B-2s operated from
Diego Garcia and an undisclosed "forward operating location". Other
sorties in Iraq have launched from Whiteman AFB. As of
September 2013[update] the longest combat mission has been 44.3
hours. "Forward operating locations" have been previously
Andersen Air Force Base
Andersen Air Force Base in
RAF Fairford in the
United Kingdom, where new climate controlled hangars have been
constructed. B-2s have conducted 27 sorties from Whiteman AFB and 22
sorties from a forward operating location, releasing more than
1,500,000 pounds (680,000 kg) of munitions, including 583 JDAM
"smart bombs" in 2003.
In response to organizational issues and high-profile mistakes made
within the Air Force, all of the B-2s, along with the
nuclear-capable B-52s and the Air Force's intercontinental ballistic
missiles (ICBMs), were transferred to the newly formed Air Force
Global Strike Command on 1 February 2010.
In March 2011, B-2s were the first U.S. aircraft into action in
Operation Odyssey Dawn, the UN mandated enforcement of the Libyan
no-fly zone. Three B-2s dropped 40 bombs on a Libyan airfield in
support of the UN no-fly zone. The B-2s flew directly from the
U.S. mainland across the Atlantic Ocean to Libya; a B-2 was refueled
by allied tanker aircraft four times during each round trip
In August 2011,
The New Yorker
The New Yorker reported that prior to the May 2011
Special Operations raid into Abbottabad,
Pakistan that resulted
in the death of Osama bin Laden, U.S. officials had considered an
airstrike by one or more B-2s as an alternative; an airstrike was
rejected because of damage to civilian buildings in the area from
using a bunker busting bomb. There were also concerns an
airstrike would make it difficult to positively identify Bin Laden's
remains and so concluding he was in fact dead would be
On 28 March 2013, two B-2s flew a round trip of 13,000 miles
(21,000 km) from Whiteman Air Force base in
Missouri to South
Korea, dropping dummy ordnance on the Jik Do target range. The
mission, part of the annual South Korean–United States military
exercises, was the first time that B-2s overflew the Korean peninsula.
Tensions between North and South Korea were high during; after the
exercise North Korea protested against the participation of the B-2s
and made threats of retaliatory nuclear strikes against South Korea
and the United States.
On 18 January 2017, two B-2s attacked an ISIS training camp 19 miles
(30 km) southwest of Sirte, Libya, killing around 85 militants.
The B-2s together dropped 108 500-pound precision-guided Joint Direct
Attack Munition (JDAM) bombs. These strikes were followed by an MQ-9
Reaper unmanned aerial vehicle firing Hellfire missiles. Each B-2 flew
a 34-hour, round-trip mission from Whiteman Air Force Base, Missouri
with 15 refuelings during the trip.
In a 1994 live fire exercise near Point Mugu, California, a B-2 drops
47 individual 500 lb (230 kg)-class Mark 82 bombs, which is
more than half of a B-2's total ordnance payload.
United States Air Force
United States Air Force (20 aircraft in active inventory)
Air Force Global Strike Command
509th Bomb Wing
509th Bomb Wing – Whiteman Air Force Base,
Missouri (currently has
13th Bomb Squadron
13th Bomb Squadron 2005–present
325th Bomb Squadron 1998–2005
393d Bomb Squadron
393d Bomb Squadron 1993–present
394th Combat Training Squadron
394th Combat Training Squadron 1996–present
Air Combat Command
53d Wing – Eglin Air Force Base, Florida
72d Test and Evaluation Squadron
72d Test and Evaluation Squadron (Whiteman AFB, Missouri)
57th Wing – Nellis AFB, Nevada
325th Weapons Squadron
325th Weapons Squadron – Whiteman AFB,
715th Weapons Squadron
715th Weapons Squadron 2003–2005
Air National Guard
131st Bomb Wing
131st Bomb Wing (Associate) – Whiteman AFB,
110th Bomb Squadron
Air Force Materiel Command
412th Test Wing
412th Test Wing – Edwards Air Force Base, California (has one B-2)
419th Flight Test Squadron
419th Flight Test Squadron 1997–present
420th Flight Test Squadron
420th Flight Test Squadron 1992–1997
Air Force Systems Command
6510th Test Wing – Edwards AFB, California 1989–1992
6520th Flight Test Squadron
Main article: 2008
Andersen Air Force Base
Andersen Air Force Base B-2 accident
Wreckage of the 2008 B-2 crash
On 23 February 2008, B-2 "AV-12" Spirit of Kansas crashed on the
runway shortly after takeoff from
Andersen Air Force Base
Andersen Air Force Base in
Guam. Spirit of Kansas had been operated by the 393rd Bomb
Squadron, 509th Bomb Wing, Whiteman Air Force Base, Missouri, and had
logged 5,176 flight hours. The two person crew ejected safely from the
aircraft and survived the crash. The aircraft was completely
destroyed, a hull loss valued at US$1.4 billion. After
the accident, the Air Force took the B-2 fleet off operational status
until clearing the fleet for flight status 53 days later on 15 April
2008. The cause of the crash was later determined to be moisture
in the aircraft's Port Transducer Units during air data calibration,
which distorted the information being sent to the bomber's air data
system. As a result, the flight control computers calculated an
inaccurate airspeed, and a negative angle of attack, causing the
aircraft to pitch upward 30 degrees during takeoff. This was the
first crash of a B-2 and the only loss as of 2018[update].
In February 2010, another serious incident involving a B-2 occurred at
Andersen AFB. The aircraft involved was AV-11 Spirit of Washington.
The aircraft was severely damaged by fire while on the ground and
underwent 18 months of repairs in order to enable it to fly back to
the mainland for more comprehensive repairs. Spirit of
Washington was repaired and returned to service in December
2013. At the time of the accident the USAF had no training
to deal with tailpipe fires on the B-2s.
Aircraft on display
Restored B-2 Spirit full-scale test unit on display at the National
Museum of the United States Air Force
No operational B-2s have been retired by the Air Force to be put on
display. B-2s have made periodic appearances on ground display at
various air shows.
B-2 test article (s/n AT-1000), the second of two built without
engines or instruments for static testing, was placed on display in
2004 at the National Museum of the
United States Air Force
United States Air Force near
Dayton, Ohio. The test article passed all structural testing
requirements before the airframe failed. The museum's restoration
team spent over a year reassembling the fractured airframe. The
display airframe is marked to resemble The Spirit of Ohio (S/N
82-1070), the B-2 used to test the design's ability to withstand
extreme heat and cold. The exhibit features Spirit of Ohio's nose
wheel door, with its Fire and Ice artwork, which was painted and
signed by the technicians who performed the temperature testing.
The restored test aircraft is on display in the museum's "Cold War
Specifications (B-2A Block 30)
A B-2 in formation flight with eight U.S. Navy F/A-18 Hornets and
Data from USAF Fact Sheet, Pace, Spick
Crew: 2: pilot (left seat) and mission commander (right seat)
Length: 69 ft (21.0 m)
Wingspan: 172 ft (52.4 m)
Height: 17 ft (5.18 m)
Wing area: 5,140 ft² (478 m²)
Empty weight: 158,000 lb (71,700 kg)
Loaded weight: 336,500 lb (152,200 kg)
Max. takeoff weight: 376,000 lb (170,600 kg)
Fuel Capacity: 167,000 pounds (75,750 kg)
Powerplant: 4 × General Electric F118-GE-100 non-afterburning
turbofans, 17,300 lbf (77 kN) each
Maximum speed: Mach 0.95 (550 knots, 630 mph, 1,010 km/h) at
40,000 ft altitude / Mach 0.95 at sea level
Cruise speed: Mach 0.85 (487 knots, 560 mph, 900 km/h) at
40,000 ft altitude
Range: 6,000 nmi (11,100 km (6,900 mi))
Service ceiling: 50,000 ft (15,200 m)
Wing loading: 67.3 lb/ft² (329 kg/m²)
2 internal bays for ordnance and payload with an official limit of
40,000 lb (18,000 kg); maximum estimated limit is
50,000 lb (23,000 kg).
80× 500 lb class bombs (Mk-82, GBU-38) mounted on Bomb Rack Assembly
36× 750 lb CBU class bombs on BRA
16× 2,000 lb class bombs (Mk-84, GBU-31) mounted on Rotary Launcher
16× B61 or B83 nuclear bombs on RLA (strategic mission)
AGM-154 Joint Standoff Weapon (JSOW) and AGM-158
Joint Air-to-Surface Standoff Missile (JASSM).
Spirit of Indiana sits on the ramp at
Andersen AFB in
Guam on 23 June
Spirit of New York
B-2 in flight over the
Mississippi River (St. Louis, Missouri) with
Gateway Arch and
Busch Stadium in the background
Air Vehicle No.
Time in service, status
Spirit of America
14 July 2000 – Active
Spirit of Arizona
4 December 1997 – Active
Spirit of New York
10 October 1997 – Active
Spirit of Indiana
22 May 1999 – Active
Spirit of Ohio
18 July 1997 – Active
Spirit of Mississippi
23 May 1997 – Active
Spirit of Texas
21 August 1994 – Active
Spirit of Missouri
31 March 1994 – Active
Spirit of California
17 August 1994 – Active
Spirit of South Carolina
30 December 1994 – Active
Spirit of Washington
29 October 1994 – Severely damaged by fire in February 2010,
Spirit of Kansas
17 February 1995 – 23 February 2008, crashed
Spirit of Nebraska
28 June 1995 – Active
Spirit of Georgia
14 November 1995 – Active
Spirit of Alaska
24 January 1996 – Active
Spirit of Hawaii
10 January 1996 – Active
Spirit of Florida
3 July 1996 – Active
Spirit of Oklahoma
15 May 1996 – Active, Flight Test
Spirit of Kitty Hawk
30 August 1996 – Active
Spirit of Pennsylvania
5 August 1997 – Active
Spirit of Louisiana
10 November 1997 – Active
AV-22 through AV-165
Sources: B-2 Spirit (Pace), Fas.org
Notable appearances in media
Main article: Aircraft in fiction § B-2 Spirit
United States Air Force
United States Air Force portal
Northrop Grumman B-21 Raider
List of active United States military aircraft
List of bomber aircraft
List of flying wing aircraft
List of aerospace megaprojects
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Wikimedia Commons has media related to B-2 Spirit.
B-2 Spirit fact sheet and gallery on U.S. Air Force site
B-2 Spirit page on
Northrop Grumman site
B-2 Stealth Bomber article on How It Works Daily
B-2 Spirit page at GlobalSecurity.org
Note: Northrop company designations include a wide variety of
technologies. Only aircraft, aero engines, and missiles are linked
See also: TR-3
Northrop Grumman aircraft
G-1 (floats only)
G-2 (floats only)
F9F-1 to -5
F9F-6 to -8
Apollo Lunar Module
USAAS/USAAC/USAAF/USAF bomber designations, Army/Air Force and
Fighter-bomber, in F-series
B-3 to B-202
1 Not assigned; place in numerical sequence assigned to SR-71 · 2 Not